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Impact of GOCE on lithospheric modelling in active plate margins. ESA Living Planet Symposium 2013 Edinburgh, 10-09-2013. Michael Hosse (1) , Roland Pail (1) , Martin Horwath (1) , Tetjana Romanyuk (1) , Ben Gutknecht (2) , Nils Köther (2) - PowerPoint PPT Presentation
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Impact of GOCE on lithospheric modelling in active plate margins
ESA Living Planet Symposium 2013Edinburgh, 10-09-2013
Michael Hosse(1), Roland Pail(1), Martin Horwath(1), Tetjana Romanyuk(1), Ben Gutknecht(2), Nils Köther(2)
(1) Technische Universität München, Institute of Astronomical and Physical Geodesy(2) Christian-Albrechts-Universitaet Kiel, Institute of Geosciences, Department of Geophysics
About IMOSAGA
Integrated Modelling of Satellite and Airborne Gravity data of Active plate margins
Part of DFG programme „Mass transport and mass distribution in the Earth system“ SPP 1257
Tight cooperation and interaction of geodetic and geophysical expert groups
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Project Objectives
Investigation of active continental margins for– Density distribution in 3D– Dynamic Structures (Finite Elements)– Rigidity
by usage of– Satellite gravimetry and gradiometry
(GOCE, GRACE)– Terrestrial gravimetry– Combined gravity
models (Least Squares Collocation LSC)
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Motivation
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
(Götze et al., 2011)
revised gravity field information in geophysically interesting areas
impact on static and dynamic lithospheric models
Datasources – Terrestrial data
~ 175000 point measurements (gabs, FA, BA) from different sources collected during the past 30 years
widely spread over South America
No informations available about used instruments and methods
No accuracies available
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Datasources – Digital Terrain Model
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Used datasets:- 3“ (land only)- 30“ (with bathymetry)
Available at:http://tethys.eaprs.cse.dmu.ac.uk/ACE2/
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Validation of terrestrial data – Heights
Differences to ACE2– Max.: 915 m– Min.: -1365 m– Mean: 2.8 m– STD: 53.7m
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Validation of terrestrial data – Heights
Differences to ACE2– Filtered at 80m
(~25 mGal Free-Air)
– Max.: 80 m– Min.: -80 m– Mean: 0.4 m– STD: 25,1 m
Datasources - Satellite gravity data
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Available at:http://www.goco.eu/ (Mayer-Gürr et.al: The new combined
satellite only model GOCO03s, 2012)
The satellite only model GOCO03s
GRACE: 7.5 years
GOCE: 18 months
SLR: 5 years, 5 sat
CHAMP: 8 years
Constrains: Kaula, deg > 180
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Validation of terrestrial data - Gravity
Difference terrestrial – GOCO03S (d/o 250) Difference terrestrial – EGM2008 (d/o 2190)
[mgal] GOCO03S EGM2008
Max. Diff 216.66 102.59
Min. Diff -325.72 -303.86
Mean -6.64 -1.45
RMS 24.08 10.94
Calculation schema
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Calculation schema
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Calculation schema
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Preprocessing terrestrial data
Dimension of normal equation depends on number of observations → restriction of points
Distribution of points is very inhomogeneous
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Calculated for each of the 53.000 stations in study area
Selected the stations with the smallest value q within a radius of 3 km
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Least Squares Collocation (LSC)
… signal covariances, derived from covariance model fitted consistently to (reduced) gravity gradients and (reduced) terr. data
… noise covariances: - terrestrial data: empirical - satellite gravity data: covariance propagation
(including omission error !!!)
BIG advantage: we obtain error estimates:
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Input data & stochastic models
Satellite data (reduced):• Synthetized from GOCO03S, on grid• Error information: - commission part: derived by full covariance propa- gation from GOCO03S variance-covariance matrix - omission part (> d/o 250) : derived by variance propagation from EGM2008 variances
Terrestrial & altimetry data:• Terrestrial data: 9910 points, irregularly distributed• Altimetry data (DTU10): 2353 points, on grid• Error information: according to quality criterion,
~10 mGal (land), ~4-5 mGal (ocean)
60
40
20
0
-20
-40
-60
mGal
60
40
20
0
-20
-40
-60
mGal
Results
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Output field [mGal] Error estimates [mGal]
• Larger errors where only satellite data available (mainly omission part!!!)
• Realistic error estimates.
Restore & Validation with EGM2008
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Restore (GOCO d/o 100 + topo-iso) IMOSAGA01C
Free-air anomalies Bouguer anomalies
IMOSAGA01C EGM2008
mGal
IMOSAGA01C EGM2008 difference
Restore & Validation with EGM2008
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Restore (GOCO d/o 100 + topo-iso) IMOSAGA01C
mGal
difference
• Improved long-wavelength behaviour• Large differences in regions without
terrestrial gravity• Geophysical interpretation (Kiel)
IMOSAGA01C makes more sense
terrestr. input
Error estimates [mGal]
Lithospheric model (IGMAS+) - Iquique
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Free-air anomalies Bouguer anomalies
IMOSAGA01C EGM2008
mGal
IMOSAGA01C EGM2008 difference
• Iquique: terrestrial gravity available
Lithospheric model (IGMAS+) - Iquique
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
• Only small variations compared to EGM2008• Lithospheric model could be confirmed
Lithospheric model (IGMAS+) - Beule
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Free-air anomalies Bouguer anomalies
IMOSAGA01C EGM2008
mGal
IMOSAGA01C EGM2008 difference
• Beule: low-quality terrestrial gravity data
Lithospheric model (IGMAS+) - Beule
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
• Significant deviation to EGM2008• Updated lithospheric model required (currently done)
Lithospheric modelling
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
• In many regions due to lack of terrestrial gravity data up to now no lithospheric profile could be modelled by IGMAS+.
• In these regions, now due to GOCE data lithospheric modelling will become possible for the first time!
Summary and conclusions
Significant improvement of regionalgravity field models through combinationof terrestrial and satellite dataMain benefit in areas with terrestrial data gaps, but also concerning the consistency in the long to medium wavelengthsProof of a clear impact of GOCE for lithospheric modelling, especially in topographically challanging regions
Methodology also usable for validation of inhomogenous gravity databasesEstablished processing procedure can be applied worldwide (also with low-quality terrestrial data)
Updated lithospheric models will be available soon
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
Final conclusion
ESA Living Planet Symposium 2013,Edinburgh, September 09-13 2013
GOCE rocks …